This is when you need an HDMI switch, a splitter, or both

A splitter allows a single peripheral to output to multiple displays.
Ars Technica

3.5mm audio/mic splitter is creating loud noises.

I recently bought a audio/mic splitter (Splitter in mention in case it helps( https://www.amazon.co.uk/KingTop-Headse ... t+splitter) in order to use the headset that ...
TV Technology

Violet Audio releases DX16 audio splitters

At the NAMM convention in Anaheim, CA, Australia-based Violet Audio displayed the DX16XI and DX16XT multichannel audio splitters. Both units can handle up to 16 channels of input, offering a full ...
EDN

Laptop Audio-Out Splitter Circuit Diagram

This active splitter for laptop audio-out is powered from a USB and provides individual channel gain of 39 dB and individual volume control of a head-phone channel. The circuit uses two TDA2822M audio ...